Hi All,
As Dr.Simon mentioned about classification in EU is based on risk, Higher risk = higher classification, and
Essential Requirements Checklist helps determine classification.
In the US, the FDA determines the device class using medical specialty panels, safety and efficacy. Life sustaining devices are automatically Class III…. Not so in the EU.

Can you give us an example for any medical device that classified in US and EU, is there any difference?
For Example:
Device: Blood Pressure Cuff
Definition:
A blood pressure cuff is a device that has an inflatable bladder in an elastic sleeve(cuff) with a mechanism for inflating the bladder. The cuff is used to determine a subject’s blood pressure.
Regulation Medical Specialty:Cardiovascular
Class:II

In EU:
Blood pressure cuff
• Invasive or non-invasive: non-invasive
– Doesn’t channel or store fluids for eventual infusion
– Doesn’t modify blood or other body fluids
– Doesn’t come into contact with injured skin
• Not an active device
• No special rules apply
• Class: I by Rule 1

Hint use this link:
FDA:accessdata.fda.gov
EU:ec.europa.eu/commission